JP4705836B2 - Protective film for optics - Google Patents

Description

  The present invention relates to an optical protective film used in manufacturing a polarizing plate used for a liquid crystal display. More specifically, the present invention relates to an optical protective film provided with antistatic properties, easy cleaning of contaminants, and scratch prevention functions.

  A general optical protective film has a structure of surface protective layer / water resistant layer / antistatic layer / base film / antistatic layer / adhesive layer / separate film layer, and one side of the base film (separate film layer) Side) is the side to be bonded to the polarizing plate and consists of a separate film layer, an adhesive layer and an antistatic layer. The adhesive layer uses an adhesive with little adhesive residue, and the antistatic layer has an antistatic function. ing. The other surface of the optical protective film is composed of an antistatic layer, a water resistant layer and a surface protective layer. The antistatic layer is as described above, and the water resistant layer is formed by removing the antistatic layer from the external environment (humidity). There is a function to minimize the influence, and the surface protective layer has many functions.

  At the time of manufacturing a polarizing plate used for liquid crystal displays, an optical protective film is bonded to the surface of the polarizing plate so that the polarizing plate is not soiled or scratched, and the optical protective film is peeled off from the polarizing plate at the time of use. Is.

  The reason for imparting an antistatic function to the adhesive layer side of the protective film for optics is that defective products may occur due to dust generated by the process of manufacturing a polarizing plate or static electricity generated when peeling from the polarizing plate. So to prevent it.

  In addition, the surface protective layer on the other surface different from the adhesive layer of the optical protective film is provided with antistatic, scratch prevention, easy cleaning of contaminants, and the like. The necessity to give each is as follows. The antistatic function is as described above, and the scratch prevention function is intended to prevent scratches that occur during the manufacturing process of the polarizing plate, and in particular, the polarizing plate and the optical protective film are attached with a roll. When aligning, cut according to the required specifications as a polarizing plate, and when it is laminated and stored, or when it is extracted during storage, it is easy to be damaged, so it is for dealing with these .

  Contaminant easy-cleaning properties: Adhesive attached to protective layer when laminating polarizing plate and optical protective film, or attached when laminated and stored, cut according to necessary specifications as polarizing plate This is because the pressure-sensitive adhesive or the like contaminates the surface of the optical protective film and becomes a problem as a defective product in appearance inspection, so that it can be easily wiped off. As a method for removing the adhesive attached to the optical protective film, for example, there is a method of performing dry wiping or wiping with a cloth soaked with an organic solvent such as alcohol or ethyl acetate. Contaminant easy-cleaning properties are required during such wiping.

As an example of the production of an optical protective film having the above functions, an acrylic pressure-sensitive adhesive is applied to one side of the base film, and a silicone acrylate is applied to the other side of the base film that has been subjected to antistatic treatment. Example of coating (see Patent Document 1) that prevents the blocking of the film during stacking by sticking out of the adhesive of the protective film for optical use and the function of easily cleaning contaminants, and polyvinyl alcohol or polyethyleneimine on the surface protective layer. Examples have been proposed in which a long-chain alkylated copolymer or the like is applied and a function that prevents the adhesive protruding from the cut surface from adhering to the surface of the optical protective film is given (see Patent Documents 2 and 3). ing.
In addition to the above-mentioned antistatic properties, scratch resistance and easy cleaning of contaminants, the surface protective layer of the optical protective film has printing suitability (printer ink suitability for process control), film substrate, Adhesion and scratch resistance are also required.

JP 2001-305346 A JP 11-256115 A JP 11-256116 A

  However, the proposed technique does not satisfy all the functions described above. Moreover, there is a demand for a surface protective layer forming material for an optical protective film that has higher performance than before. From the current 3-coat system (surface protective layer / water resistant layer / antistatic layer / base film) to the 2-coat system (surface protective layer / antistatic layer / base film) For the purpose of simplifying the production method, there is also a demand for a change in the configuration system to a one-coat system (antistatic surface protective layer / base film).

Therefore, the object of the present invention is to provide antistatic properties, scratch resistance, easy cleaning of contaminants (solvent resistance is also required because it may be cleaned with an organic solvent), printability (used for process control) To provide an optical protective film having adhesiveness with a substrate film, transparency, and the like.
Furthermore, an object of the present invention is to provide an optical protective film capable of a one-coat system of antistatic surface protective layer / base film as the structure of the surface protective layer.

The above object is achieved by the present invention having the following constitution.
1. From a base film, an adhesive layer provided on one surface of the base film, and an antistatic surface protective layer (surface protective layer having an antistatic function) provided on the other surface of the base film In the optical protective film, the antistatic surface protective layer is coated with a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule , a carbon nanotube (B), and a polyisocyanate (C). An optical protective film , wherein a coating is formed as a forming component with one coat .

2. Resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a resin having an active hydrogen group in the molecule, a perfluoroalkyl compound having at least one active hydrogen group in the molecule, and a polyisocyanate 2. The protective film for optics according to 1 above, which is a reaction product of

3. 2. The optical protective film as described in 1 above, wherein the resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule contains 0.0001 to 30% by mass of a perfluoroalkyl group component.

4). ^2. The optical protective film as described in 1 above, wherein the surface resistance value is from 10 ³ to 10 ¹⁰ Ω / cm ² .
5. 2. The optical protective film as described in 1 above, wherein the total light transmittance is 70% or more and the haze value is 0 to 20%.

6). 2. A coating material for forming an antistatic surface protective layer in the optical protective film as described in 1 above, comprising a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a carbon nanotube (B), A paint for forming an antistatic surface protective layer, comprising a polyisocyanate (C) dissolved in an organic solvent.

7). Resin (A) is 50-99.9 mass% of the total amount (100 mass%) of resin (A) and carbon nanotube (B), and carbon nanotube (B) is 0.1-25 mass%. 7. The paint according to 6 above.
8). 7. The coating material according to 6 above, further comprising adding a polyisocyanate before use or containing a stabilized polyisocyanate.

  According to the present invention, the construction system of the surface protective layer of the optical protective film comprises a one-coat system such as an antistatic surface protective layer / base film, and is antistatic, scratch resistant, easy to clean contaminants, Provided is an optical protective film excellent in printability, adhesion to a substrate film and transparency.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained a base film, an adhesive layer provided on one side of the base film, and a charging provided on the other side of the base film. An optical protective film comprising a protective surface protective layer (hereinafter sometimes referred to simply as “surface protective layer”), the surface protective layer comprising a resin having an active hydrogen group and a perfluoroalkyl group in the molecule, and a carbon nanotube It was found that an optical protective film having an excellent function can be obtained by forming polyisocyanate and polyisocyanate as a film-forming component.

Next, the present invention will be described in more detail with reference to preferred embodiments.
The optical protective film of the present invention comprises a base film, an adhesive layer provided on one surface of the base film, and a surface protective layer provided on the other surface of the base film. That is, the structure of the optical protective film on the surface protective layer side is characterized by the structure of a one-coat system such as a surface protective layer / base film, and the structure of a conventional three-coat system (surface protective layer / water resistant layer). / Antistatic layer / base film) or a two-coat system construction (surface protective layer / antistatic layer / base film). That is, the surface protection layer is excellent in cost performance by reducing the number of coatings during production.

  Next, the surface protective layer will be described in detail. The surface protective layer is formed using a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a carbon nanotube (B), and a polyisocyanate (C) as a film forming component. Is preferably dissolved in a solvent or the like, or coated on a substrate film as a coating material for forming a surface protective layer and dried without solvent to form a surface protective layer. The surface protective layer forming coating in this case contains a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a carbon nanotube (B), and a polyisocyanate (C).

  Resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule includes a resin having an active hydrogen group in the molecule, a perfluoroalkyl compound having at least one active hydrogen group in the molecule, polyisocyanate, It is preferable to use a product obtained by reacting. When these are reacted, they may be reacted all at once, or the reaction obtained after first reacting a perfluoroalkyl compound having at least one active hydrogen group in the molecule with a polyisocyanate. The product may be reacted with a resin having an active hydrogen group in the molecule, but the latter reaction method is more preferred.

  Examples of the resin having an active hydrogen group in the molecule include polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, acetal group-modified polyvinyl alcohol, butyral group-modified polyvinyl alcohol, silanol group-modified polyvinyl alcohol, ethylene- Vinyl alcohol copolymer, ethylene-vinyl alcohol vinyl acetate copolymer resin, acrylic resin, epoxy resin, phenoxy resin, phenoxy ether resin, phenoxy ester resin, fluorine resin, melamine resin, alkyd resin, phenol resin, polyether, Examples thereof include polyester, celluloses, chitosan, and urethane resin. Furthermore, at least one selected from these is preferably used. Of these, ethylene-vinyl alcohol copolymer, partially saponified polyvinyl alcohol and phenoxy resin are particularly preferable.

Examples of the active hydrogen group in the resin having an active hydrogen group in the molecule include a hydroxyl group (—OH), a carboxyl group (—COOH), an amino group (—NRH (R: hydrocarbon group), —NH _2, etc.). And a thiol group (—SH), among which a hydroxyl group and an amino group are preferably used. In the resin having an active hydrogen group in the molecule, the active hydrogen group can be used for the reaction as it is, but when the resin molecule does not have an active hydrogen group, a treatment such as modification is performed. An active hydrogen group can be added.

  The perfluoroalkyl group in the resin (A) will be described. In order to obtain the resin (A), it is preferable to use a perfluoroalkyl compound having at least one active hydrogen group in the molecule and react with the resin having an active hydrogen group in the molecule via polyisocyanate. Therefore, the perfluoroalkyl compound will be described. As the perfluoroalkyl compound having at least one active hydrogen group in the molecule used in the present invention, for example, the following compounds are preferably used (in which the active hydrogen group is used for modification). In addition, an epoxy-modified perfluoroalkyl compound is also included, but it is included because it reacts with an isocyanate group and is contained in the resin (A)).

(1) Alcohol type

上記のエポキシ化合物はポリオール、ポリアミド、ポリカルボン酸などとの活性水素基含有化合物と反応させて末端水酸基を有するようにして使用する。 (2) Epoxy type

The above epoxy compound is used so as to have a terminal hydroxyl group by reacting with an active hydrogen group-containing compound such as polyol, polyamide or polycarboxylic acid.

(3) Amine type

(4) Carboxylic acid type

  The perfluoroalkyl compounds having an active hydrogen group in the molecule listed above are preferable compounds used in the present invention, but the present invention is not limited to these exemplified compounds. Accordingly, not only the above-exemplified compounds but also other compounds that are currently commercially available and can be easily obtained from the market can be preferably used in the present invention. Particularly preferred compounds in the present invention are perfluoroalkyl compounds having one hydroxyl group or amino group.

  As said polyisocyanate which can react with the said perfluoroalkyl compound, what is conventionally used for manufacture of a polyurethane can be used and it does not specifically limit. Preferred examples of the polyisocyanate include toluene-2,4-diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, 4,4′-methylenebis (phenylene isocyanate) (MDI), durylene diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), 1,5- Aromatic diisocyanates such as naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate and 4,4′-diisocyanate dibenzyl, methylene diisocyanate Aliphatic isocyanates such as socyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate and 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), Obtained by reacting 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, cycloaliphatic diisocyanates such as hydrogenated MDI and hydrogenated XDI, or these diisocyanate compounds with low molecular weight polyols or polyamines so that the terminal is isocyanate. Naturally, polyurethane prepolymers and the like can also be used.

  In particular, diisocyanates having different reaction rates in the primary reaction and the secondary reaction in the diisocyanate are preferable. Examples of such a diisocyanate include isophorone diisocyanate. Furthermore, a combination with a catalyst in which a reaction difference between the primary reaction and the secondary reaction is remarkably shown by the reaction catalyst effect is more preferable.

  The production method of the resin (A) in which the resin having an active hydrogen group in the molecule, the perfluoroalkyl compound having at least one active hydrogen group in the molecule and the polyisocyanate are reacted is not particularly limited, and is conventionally known. A method similar to that of the polyurethane can be used. For example, in the presence or absence of an organic solvent that does not contain an active hydrogen group in the molecule, first, a perfluoroalkyl compound having at least one active hydrogen group in the molecule and a bifunctional diisocyanate are used. Reaction is carried out at an equimolar number to produce a compound having a perfluoroalkyl group and a terminal isocyanate group in the same molecule. Next, a resin having an active hydrogen group and a perfluoroalkyl group in the same molecule is produced by reacting this compound with an active hydrogen group in the resin having an active hydrogen group in the molecule. The reaction temperature is usually 20 to 150 ° C., preferably 60 to 110 ° C., and finally the reaction is completed until almost no isocyanate groups are present.

  The resin (A) may be synthesized without a solvent or may be produced using an organic solvent. Preferable examples of the organic solvent include methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, and butyl acetate. Acetone, cyclohexane, tetrahydrofuran, dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethyl sulfoxide, perchlorethylene, trichloroethylene, methyl cellosolve, butyl cellosolve, cellosolve acetate, and the like.

  When a resin having an active hydrogen group and a perfluoroalkyl group in the same molecule is produced, the perfluoroalkyl group in the resin is 0.0001 to 30% by mass, preferably 0.01 It is desirable to contain ~ 20 mass%. When there are many perfluoroalkyl groups (when it exceeds 30 mass%), when preparing a coating using this resin, the dissolution stability of the coating is inferior, or due to the presence of an unreacted perfluoroalkyl compound in the coating, Since the phenomenon of repelling the ink used for quality process control of the optical protective film finally obtained may occur, it is not preferable. On the other hand, if the amount of perfluoroalkyl groups is small (less than 0.0001% by mass), it is not preferable because of poor cleaning performance of contaminants, solvent resistance, and control of humidity of the outside air.

  The carbon nanotube (B) used in the present invention is not particularly limited, and examples thereof include a material having a single-layer structure in which carbon hexagonal mesh surfaces are closed in a cylindrical shape or a multilayer structure in which cylindrical structures are arranged in a nested manner. Can be mentioned. The shape is a hollow cylinder having a diameter of 1 to 100 nm and a length of 1 to 50 μm. The method for producing the carbon nanotube is not particularly limited, and the carbon nanotube can be obtained by chemical vapor deposition, catalytic vapor deposition, chemical vapor deposition, arc discharge, laser evaporation, and the like. Either can be used in the present invention.

  By using the hollow cylindrical carbon nanotube as described above, the transparency and film forming property of the coating film are improved. In addition, the antistatic protective layer using carbon nanotubes having ultrafine and high conductivity can exhibit the antistatic effect with a small content compared to the conventional antistatic protective layer using carbon black.

  The amount of the resin (A) and the carbon nanotube (B) used is 50 to 99.9% by mass, preferably 70 to 100% by mass of (A) and (B). 99% by mass, and the carbon nanotube (B) is 0.1 to 50% by mass, preferably 1 to 30% by mass. If the amount of (A) used exceeds 99.9% by mass, the antistatic function cannot be obtained, and this is not preferred. If it is less than 50% by mass, the stability of the paint and the scratch resistance of the finally obtained protective film for optical use are low. Since it falls, it is not preferable. On the other hand, if the amount of (B) used exceeds 50% by mass, the solvent resistance and scratch properties of the surface protective layer are deteriorated and the coating solution becomes unstable. This is not preferable because the charging performance of the layer is lowered.

  As the polyisocyanate (C) for forming the surface protective layer, known ones conventionally used can be used and are not particularly limited. For example, dimer of 2,4-toluylene diisocyanate, triphenylmethane triisocyanate, tris- (p-isocyanatephenyl) thiophosphite, polyfunctional aromatic isocyanate, polyfunctional aromatic aliphatic isocyanate, polyfunctional aliphatic Examples thereof include blocked polyisocyanates such as isocyanate, fatty acid-modified polyfunctional aliphatic isocyanate, and blocked polyfunctional aliphatic isocyanate, and polyisocyanate prepolymers. Of these, it is possible to use either an aromatic or aliphatic type, preferably a modified product such as diphenylmethane diisocyanate and tolylene diisocyanate for an aromatic type, hexamethylene diisocyanate and isophorone diisocyanate for an aliphatic type, and a molecule. A urethane prepolymer obtained by reacting a polyisocyanate multimer or an adduct with another compound, or a low molecular weight polyol or polyamine so as to be a terminal isocyanate is preferable. Etc. are also preferably used. These are exemplified below with structural formulas, but are not limited thereto.

  The amount of these polyisocyanates (C) used is 5 to 100 parts by mass, preferably 5 to 55 parts by mass with respect to 100 parts by mass of the resin (A) and the carbon nanotube (B). If the amount of (C) used exceeds 100 parts by mass, it is not preferable because the usable time of the paint is reduced, and if it is less than 5 parts by mass, the crosslinking density of the surface protective layer is reduced.

  In the coating material for forming the surface protective layer, if necessary, a curing catalyst, a reaction inhibitor and other additives can be appropriately used. Examples of the curing catalyst include dibutyltin laurate, dioctyltin laurate, stannous octoate, lead octylate, tetra-n-butyl titanate, and salts of organic or inorganic acids and organometallic derivatives such as triethylamine. And organic amines such as diazabicycloundecene catalysts. Examples of the reaction inhibitor include phosphoric acid, acetic acid, tartaric acid, phthalic acid, and formic acid ester.

  Furthermore, for the purpose of imparting slipperiness and water resistance, for example, siloxane oil and / or modified siloxane oil (for example, polydimethylsiloxane, polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polydimethylsiloxane, etc.), various types Additives such as waxes, long chain alkyl modified polymers, fluorine modified polymers and siloxane modified polymers can be added.

  Furthermore, for the purpose of use in combination with other antistatic agents, for example, polyvinyl alcohol, cation-modified polyvinyl alcohol, alkali metal salt-containing polyether, alkali metal salt-containing siloxane-modified polyether, alkali metal salt-containing ether polyurethane, polyamine, quaternary Organic conductive materials such as cation salt-containing acrylic resins, specially modified polyesters, special cationic resins, cellulose derivatives, polyacetylene, polyparaphenylene, polythiophene, polypyrrole, polyaniline and sulfonated polyaniline, carbon black, tin oxide, zinc oxide and Additives such as metal oxides such as titanium oxide and various metal alkoxides and conductive filler-containing polymers such as ITO powder can be added.

  Among the compounds, alkali metal salt-containing polyether, alkali metal salt-containing siloxane-modified polyether and alkali metal salt in the alkali metal salt-containing ether polyurethane, for example, lithium perchlorate, lithium bistrifluoromethanesulfonimide, Lithium borofluoride, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium pentafluoroethanesulfonate, lithium bispentafluoroethanesulfonimide, tetraethylammonium borofluoride, tetraethylammonium hexafluorophosphate and potassium bistrifluoromethanesulfone An imide etc. can be mentioned.

  In the case of forming the surface protective layer of the present invention, the resin contains a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a carbon nanotube (B), and a polyisocyanate (C). The surface protective layer forming paint is used. In addition, when the said polyisocyanate (C) is stabilized polyisocyanate, you may mix | blend at the time of preparation of a coating material, and you may mix | blend just before use of a coating material. Moreover, when the said polyisocyanate (C) is not stabilized polyisocyanate, it is preferable to mix | blend just before use of a coating material. The paint may be prepared without a solvent or may be prepared using an organic solvent. Preferable examples of the organic solvent include methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate and butyl acetate. Acetone, cyclohexane, tetrahydrofuran, N-methyl-2-pyrrolidone, dioxane, toluene, xylene, dimethylformamide, dimethyl sulfoxide, perchlorethylene, trichloroethylene, methyl cellosolve, butyl cellosolve and cellosolve acetate can also be used. Although the solid content of the coating material prepared using the organic solvent is not particularly limited, it is preferably about 3 to 95% by mass.

  As the base film used for the optical protective film of the present invention, for example, a film containing polyester, polyimide, polyethylene, polypropylene or the like as a component is used. Particularly preferred is a biaxially stretched polyethylene terephthalate film having an appropriate and necessary strength suitable for an optical protective film. The thickness of a base film becomes like this. Preferably it is 20-100 micrometers, More preferably, it is 25-40 micrometers. These base films may be subjected to corona treatment, antistatic treatment, easy adhesion treatment, and the like as necessary.

  The optical protective film of the present invention can be produced by a conventionally known method using the above-mentioned coating material for forming the surface protective layer, and the production method itself is not particularly limited. Moreover, as for materials other than surface protective layer forming materials, such as a base film and an adhesion layer forming material, all can use a well-known material and are not specifically limited. When forming the surface protective layer of the optical protective film of the present invention, the surface protective layer-forming coating material of the present invention is dried on the surface of the base film (the back surface is an adhesive layer) by a conventionally known method. Is applied to form a film.

  The surface protective layer thus obtained has an active hydrogen group in the molecule and a surface energy difference between the resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule and the carbon nanotube (B). The active hydrogen groups in the resin (A) having a perfluoroalkyl group are hydrophilic and thus are oriented more on the surface of the base film to improve the adhesion of the surface protective layer to the base film. On the other hand, many perfluoroalkyl groups having low surface energy and carbon nanotubes are oriented on the opposite side (air side) of the base film, thereby imparting antistatic properties and antifouling properties.

  The polyisocyanate (C) forming the surface protective layer crosslinks the components in the material for forming the surface protective layer, so that it has solvent resistance and scratch resistance (up to surface hardness) that can withstand contamination removal of the surface protective layer. Further improvement can be achieved. The antistatic function is maintained by incorporating carbon nanotubes in the surface protective layer-forming coating material.

Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples and comparative examples, but the present invention is not limited thereto. Moreover, in the following sentence, “part” indicates mass part, and “%” indicates mass%.
[Synthesis Examples 1-2]
A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube and a reflux condenser is replaced with nitrogen gas, and then a predetermined amount of polyisocyanate compound, reaction catalyst and organic solvent (solid content = 30%) is charged. Warm to ° C. Subsequently, a predetermined perfluoroalkyl compound was added to a predetermined concentration and stirred at 80 ° C. in a nitrogen stream until uniform. Table 1 shows the composition and properties of the obtained oligomer having a perfluoroalkyl group and an isocyanate group.

The perfluoroalkyl compound (a) in Table 1 has the following structure.
A-1) CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OH
A-2) CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ NH ₂

[Synthesis Examples 3 to 6]
A reaction vessel equipped with a stirrer, reflux condenser, thermometer, nitrogen blowing tube and manhole was replaced with nitrogen gas, and then a predetermined amount of a resin (base resin) having an active hydrogen group in the molecule and a solvent were added, and 60 ° C. To dissolve the resin. Subsequently, a predetermined amount of the oligomer having the perfluoroalkyl group and the isocyanate group produced above was added, and the reaction was carried out at 90 ° C. until no absorption due to a free isocyanate group of 2,270 cm ⁻¹ was observed in the infrared absorption spectrum. Reaction was performed. Table 2 shows the raw material composition and properties of a resin having an active hydrogen group and a perfluoroalkyl group in the molecule.

F-NCO (H); oligomer having perfluoroalkyl group and isocyanate group EVOH; ethylene vinyl alcohol, trade name: F104 (ethylene copolymerization ratio = 32 mol%, melt index = 4.5 g / min .; 190 ° C. , 2,160g), manufactured by Kuraray Co., Ltd.)
-PVA; partially saponified polyvinyl alcohol, trade name: PVA-217 (degree of saponification = 87 to 89, degree of polymerization = 1,700), manufactured by Kuraray Co., Ltd.)
YP-50S; phenoxy resin, trade name: phenototoy YP-50S (weight average molecular weight = 40,000, manufactured by Toto Kasei Kogyo Co., Ltd.)
BL-1; butyral group / acetyl group-containing polyvinyl alcohol copolymer, trade name: BL-1 (hydroxyl group = 36 mol%, acetyl group = 3 mol% or less, butyral degree = 63 mol%, manufactured by Sekisui Chemical Co., Ltd.) )
・ MEK; Methyl ethyl ketone ・ DMF; Dimethylformamide

[Examples 1-4, Comparative Examples 1-2]
The coating compositions for forming the surface protective layer of Examples 1 to 4 and Comparative Examples 1 and 2 (solid content 5%) were prepared according to the compositions in Tables 3 and 4.

Aging condition: 40 ° C., 2 days PHDI: HDI biuret type, Duranate 24A-100 (manufactured by Asahi Kasei Chemicals Corporation)
MEK; methyl ethyl ketone, DMF, dimethylformamide, modified polymer (S), resin having an active hydrogen group and a perfluoroalkyl group in the molecule

  The paint used for the optical protective film of the present invention was prepared by dissolving or dispersing the perfluoroalkyl copolymer (A) and the carbon nanotube (B) in an organic solvent. Any known dispersion method may be used as the dissolution or dispersion method, and is not particularly limited. For example, a paint is prepared by dispersing with a ball mill, basket mill, sand mill, roll mill, attritor, wet jet mill, dissolver, paint shaker, extrusion mixer, homogenizer, ultrasonic disperser or the like. A polyisocyanate-based cross-linking agent is added to this paint and used as a paint for forming a surface protective layer.

  Using each paint obtained in each Example and Comparative Example, it was applied to the surface of a 38 μm thick polyethylene terephthalate (PET) film (manufactured by Toray) by gravure printing so that the thickness after drying would be 0.5 μm. After that, the solvent was dried in a dryer. When the coating materials of Examples 1 to 4 and Comparative Example 2 were used, the surface protective layer was formed by aging in an oven at 40 ° C. for 48 hours after application and drying. Comparative Example 1 was evaluated by drying at 110 ° C. for 90 seconds without aging.

  Next, an adhesive composition was prepared according to the following formulation. An adhesive layer was formed on the back surface of each PET film on which the surface protective layer had been formed by applying a gravure roll so that the thickness after drying was 25 μm, and optical protective films of Examples and Comparative Examples were obtained.

[Adhesive composition]
・ SK Seikadyne 1491H (manufactured by Soken Chemical Co., Ltd.) 100 parts ・ Curing agent L-45 (manufactured by Soken Chemical Co., Ltd.) 0.9 parts

[Test example]
The performances of the coating films of the surface protective layers and the protective films for optics of the Examples and Comparative Examples obtained above were tested for the following items, and the results shown in Table 5 were obtained.
<Surface resistance value>
The antistatic property of the optical protective film is measured using MCP-HT450 manufactured by Mitsubishi Chemical Corporation. The measurement conditions were a temperature of 23 ° C., a humidity of 65% RH, an applied voltage of 100 V, and 30 seconds. In order to exert the antistatic effect, 1 × 10 ¹¹ Ω / cm ² or less is desirable.

<Transparency>
Using Suga Test Instruments Co., Ltd. direct reading haze computer HGM-2DP, the total light transmittance and haze value of the optical protective film were measured.
Haze value = measured value-base material haze value

<Ethyl acetate resistance>
1 g of ethyl acetate was hung on the surface of the optical protective film, and the appearance of the coating film of the surface protective layer when rubbed with a load of 50 g / cm ² was observed.
○: There is no change in the coating film appearance of the surface protection layer △: The coating film appearance of the surface protection layer is slightly changed ×: The coating film appearance of the surface protection layer is changed

<Easy cleaning of contaminants>
1 g of the pressure-sensitive adhesive composition (SK Seikadyne 1491H (manufactured by Soken Chemical Co., Ltd.) / Curing agent L-45 (manufactured by Soken Chemical Co., Ltd.) = 100 / 0.9) was rubbed against the coating film of the surface protective layer, and Kimwipe (Registered trademark) The ease of cleaning at the time of wiping was confirmed.
○: Adhesive deposits can be easily washed △: Adhesive deposits remain a little ×: Adhesive deposits cannot be washed

<Scratch resistance>
The coating film of the surface protective layer of the optical protective film was rubbed with Scotch Bright (manufactured by Sumitomo 3M Co., Ltd.) under a load of about 10 g / cm ² , and the surface was visually checked for scratches.
○: 0 or more and less than 5 scratches that can be confirmed Δ: 5 or more and less than 10 scratches that can be confirmed ×: 10 or more scratches that can be confirmed

<Adhesion>
The adhesion between the coating film of the surface protective layer of the protective film for optics and the substrate PET film was measured by a cross cut test (cellophane tape peeling cross-cut method).

<Slipperiness>
The dynamic friction coefficient of the optical protective film is measured using HEIDON-14DR manufactured by Shinto Kagaku Co., Ltd. The measurement conditions were a temperature of 23 ° C., a humidity of 65% RH, and an average value of 5 measurements. The dynamic friction coefficient is preferably in the range of 0.18 to 0.28.

<Printability>
Magic Ink No. manufactured by Teranishi Chemical Industry Co., Ltd. 500 was written on the coating surface of the surface protective layer, and the ink writing situation was observed.
○: The writing status of magic ink is good. △: There is a slight ink repellency, but there is no problem. ×: The ink cannot be repelled and written.

As described above, according to the present invention, in addition to antistatic properties, scratch resistance (scratch properties), and easy cleaning of contaminants (solvent resistance is required for cleaning with an organic solvent), printability ( Printer ink used for process control), optical protective film with adhesion and transparency to the substrate, etc. can be created, and 1 coat system that combines surface protection function and antistatic function is possible An optical protective film is provided.

Claims (8)

In an optical protective film comprising a base film, an adhesive layer provided on one side of the base film, and an antistatic surface protective layer provided on the other side of the base film,
The antistatic surface protective layer is coated in one coat using a resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule , a carbon nanotube (B), and a polyisocyanate (C) as a film forming component. protective optical film characterized by being formed a.   Resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule, a resin having an active hydrogen group in the molecule, a perfluoroalkyl compound having at least one active hydrogen group in the molecule, and a polyisocyanate The protective film for optics according to claim 1, which is a reaction product of   The optical protective film according to claim 1, wherein the resin (A) having an active hydrogen group and a perfluoroalkyl group in the molecule contains 0.0001 to 30% by mass of a perfluoroalkyl group component. The optical protective film according to claim 1, wherein the surface resistance value is 10 ³ to 10 ¹⁰ Ω / cm ² .   The optical protective film according to claim 1, wherein the total light transmittance is 70% or more and the haze value is 0 to 20%. A paint for forming an antistatic surface protective layer in the optical protective film according to claim 1, wherein the resin (A) and carbon nanotube (B) have an active hydrogen group and a perfluoroalkyl group in the molecule. And a polyisocyanate (C) dissolved in an organic solvent, a coating composition for forming an antistatic surface protective layer.   Resin (A) is 50-99.9 mass% of the total amount (100 mass%) of resin (A) and carbon nanotube (B), and carbon nanotube (B) is 0.1-50 mass%. The paint according to claim 6.   Furthermore, the polyisocyanate is added before use, or the coating material of Claim 6 containing the stabilized polyisocyanate.